PLANT AND METHOD FOR LOW-TEMPERATURE AIR SEPARATION

Abstract

The invention relates to a plant for low-temperature air separation, having a rectification column system comprising a high-pressure column, a divided low-pressure column and a divided argon column, and a cold box system comprising a first cold box and a second cold box. The high-pressure column is arranged beneath the lower section of the low-pressure column. The high-pressure column together with the lower section of the low-pressure column is located in the first cold box, and the top section of the low-pressure column in the second cold box. It is proposed to arrange the base section of the argon column in the first cold box and the top section of the argon column in the second cold box, or vice versa. The present invention likewise provides a corresponding method.

Claims

1. A plant for low-temperature air separation, having a rectification column system comprising a high-pressure column, a low-pressure column and an argon column, and a cold box system having a first cold box perimeter and a second cold box, wherein the low-pressure column is divided into at least a base section and a top section, the base section and the top section of the low-pressure column are arranged next to one another in such a manner that an orthogonal projection of the base section of the low-pressure column onto the horizontal plane does not intersect with an orthogonal projection of the top section of the low-pressure column onto the horizontal plane, the high-pressure column is arranged below the base section of the low-pressure column in such a manner that an orthogonal projection of the high-pressure column onto the horizontal plane intersects with the orthogonal projection of the base section of the low-pressure column onto the horizontal plane, the high-pressure column together with the base section of the low-pressure column is located in the first cold box and the top section of the low-pressure column is arranged in the second cold box, wherein the argon column is divided at least into a base section and a top section, wherein the base section and the top section of the argon column are arranged next to one another in such a manner that an orthogonal projection of the base section of the argon column onto the horizontal plane does not intersect with an orthogonal projection of the top section of the argon column, wherein the base section of the argon column is arranged in the first cold box, and the top section of the argon column is arranged in the second cold box, or the base section of the argon column is arranged in the second cold box and the top section of the argon column is arranged in the first cold box.

2. The plant according to claim 1, wherein the argon column is designed as a crude argon column and further a pure argon column is provided, wherein the pure argon column is arranged in the first cold box or the second cold box, in particular in the cold box in which the top section of the argon column designed as a crude argon column is arranged.

3. The plant according to claim 1, wherein the rectification column arrangement has a pure oxygen column.

4. The plant according to claim 3, wherein the pure oxygen column is arranged in the first cold box, the second cold box or an additionally provided third cold box.

5. The plant according to claim 3, wherein the pure oxygen column and the base section of the argon column are arranged side by side in such a way that an orthogonal projection of at least one upper part of the pure oxygen column onto the horizontal plane does not overlap with the orthogonal projection of the base section of the argon column onto the horizontal plane.

6. The plant according to claim 3, wherein the pure oxygen column has a feed point for a first transfer liquid and the base section of the argon column has an extraction point for the first transfer liquid, wherein the pure oxygen column and the base section of the argon column are arranged such that the extraction point for the first transfer liquid is geodetically above the feed point for the first transfer liquid.

7. The plant according to claim 6, wherein the extraction point for the first transfer liquid is 1 to 30, preferably 1 to 15, theoretical plates above a sump of the base section of the argon column.

8. The plant according to claim 1, wherein the base section of the argon column has a feed point for a second transfer liquid, and the top section of the low-pressure column has an extraction point for the second transfer liquid, wherein the top section of the low-pressure column and the base section of the argon column are arranged such that the extraction point for the second transfer liquid is above the feed point for the second transfer liquid.

9. The plant according to claim 1, comprising a subcooling heat exchanger which is arranged in the first or second cold box, in particular in the second cold box below the top section of the low-pressure column.

10. The plant according to claim 1, wherein the top section of the low-pressure column has a feed point for a second transfer liquid, and the base section of the argon column has an extraction point for the second transfer liquid, wherein the base section of the argon column and the top section of the low-pressure column are arranged in such a way that the extraction point for the second transfer liquid is above the feed point for the second transfer liquid.

11. The plant according to claim 10, comprising a subcooling heat exchanger which is arranged below the base section of the argon column.

12. The plant according to claim 1, in which all cold apparatus parts are arranged in the first or the second cold box and no third cold box is used.

13. A method for the low temperature separation of air, wherein a system according to claim 1.

Description

DESCRIPTION OF THE FIGURES

[0059] FIG. 1 illustrates a plant for low-temperature separation of air, which can be based on an embodiment of the invention, in the form of a simplified process flowchart.

[0060] FIG. 2 illustrates an arrangement of components of a plant designed according to an embodiment of the invention for the low temperature separation of air in a side view and in a simplified representation.

[0061] FIG. 3 illustrates an arrangement of components of a plant designed according to an embodiment of the invention for the low temperature separation of air in a plan view and in a simplified representation.

[0062] If plant components of a plant for low-temperature separation of air (hereinafter also referred to as air separation plant) are described below, the corresponding explanations also apply to a method carried out thereby and vice versa.

EMBODIMENTS OF THE INVENTION

[0063] FIG. 1 schematically shows an air separation plant which is set up to obtain an argon product and a pure oxygen product and is denoted overall by 100.

[0064] The air separation plant 100 has a rectification column system 10 which comprises a high-pressure column 11, a low-pressure column divided into a base section 12 and a top section 13, a (crude) argon column also divided into a base section 14 and a top section 15, and a pure argon column 20. A pure oxygen column is designated by 18. A block designated with 1 comprises the customary components present in an air separation plant of the illustrated type for compression, purification and cooling of the feed air, in particular also a main heat exchanger of known type. A subcooling heat exchanger is designated with 17.

[0065] The base section 12 and the top section 13 of the low-pressure column and the base section 14 and the top section 15 of the argon column are structurally separated from one another and are arranged next to one another in the sense explained above. The base section 12 and the top section 13 of the low-pressure column together functionally correspond to a conventional low-pressure column of a double column. The high-pressure column 11 and the base and top section 12, 13 of the low-pressure column therefore form a rectification column system for nitrogen-oxygen separation of a type known per se, to which is connected an argon system consisting of the base section 14 and the top section 15 of the argon column and the pure argon column 20.

[0066] In the shown exemplary embodiment, cooled and compressed feed air in the form of two material flows a, b is fed into the high-pressure column 11 or the top section 13 of the low-pressure column. The air separation plant 100 can be designed for internal compression and can be designed as desired in the frame shown here. Further compressed feed air is conducted in the form of a material flow c through a sump evaporator, not designated separately, of the pure oxygen column 18, at least partially condensed there, and then likewise, now referred to as d, fed into the top section 13 of the low-pressure column. The specific type of air feed into the column arrangement is not essential to the invention and can be designed in any desired manner (with/without a choked flow, with/without air feed into the low-pressure column or its top section 13, etc.). This also applies to the provision of turbines for cold generation, which may or may not be provided.

[0067] The high-pressure column 11 and the base section 12 of the low-pressure column are connected via a condenser evaporator 19, the so-called main condenser, to exchange heat and are designed as a structural unit. However, the invention can in principle also be used in systems in which the high-pressure column 11 and the low-pressure column (or their base section 12) are arranged separately from one another and have a separate condenser evaporator 19, i.e., not integrated into the columns.

[0068] The operation of the air separation plant 100 is directly evident from the representation according to FIG. 1. Reference is therefore made to the technical literature cited at the outset.

[0069] In particular, the base section 12 and the top section 13 of the low-pressure column are in this case fluidically coupled to one another in that head gas is transferred from an upper region of the base section 12 of the low-pressure column in the form of a material flow e to a lower region of the top section 13 of the low-pressure column. As also explained with reference to FIG. 2, the arrangement of the top section 13 of the low-pressure column and of the base section 14 of the argon column in the shown example is such that sump liquid in the form of a material flow f can run from a lower region of the top section 13 of the low-pressure column into a lower region of the base section 14 of the argon column, in which a further section of the head gas is also fed from the upper region of the base section 12 of the low-pressure column in the form of a material flow g. In this way, sump liquid is collected from the top section 13 of the low-pressure column and the base section 14 of the argon column in the sump om of the base section 14 of the argon column and can be pumped back into an upper region of the base section 12 of the low-pressure column by means of a common pump 110 in the form of a material flow h. A reverse arrangement is also possible, as mentioned.

[0070] The head gas of the foot section 14 of the argon column is transferred into a lower region of the head section 15 of the argon column, and liquid is correspondingly pumped back with a pump 120. The incorporation of the pure argon column 20 can substantially correspond to that which is routine in the art. The argon column consisting of the base section 14 and the top section 15 is therefore fluidically connected in parallel to the low-pressure column or its base section 12 and top section 13 such that corresponding head gas from an upper region of the base section 12 of the low-pressure column is also transferred into a lower region of the base section 14 of the argon column, and the sump liquid is returned from the lower region of the base section 14 of the argon column into the upper region of the base section 12 of the low-pressure column. In particular, the same pump is used, which is also used to return the sump liquid from the lower region of the top section 13 of the low-pressure column into an upper region of the base section 12 of the low-pressure column.

[0071] Furthermore, the base section 14 and the top section 15 of the argon column are fluidically coupled to one another in that head gas is transferred from an upper region of the base section 14 of the argon column into a lower region of the top section 15 of the argon column and, by means of a (further) pump, sump liquid is recirculated from a lower region of the top section 15 of the argon column into an upper region of the base section 14 of the argon column.

[0072] The pure oxygen column 18 is fed here at a feed point 18a with a transfer liquid in the form of a material flow t, which is removed from the base section 14 of the argon column at an extraction point 14a. The pure oxygen column 18 and the base section 14 of the argon column are arranged in such a way that the extraction point 14a for the transfer liquid from the base section 14 of the argon column is geodetically above the feed point 18a for the transfer liquid into the pure oxygen column 18, as a result of which it can be transferred into the pure oxygen column 18 without a pump.

[0073] The base section 14 of the argon column is furthermore fed at a feed point 14b with a further transfer liquid in the form of the material flow f already mentioned, which is removed from the top section 13 of the low-pressure column at an extraction point 13b, wherein the top section 13 of the low-pressure column and the base section 14 of the argon column in the example illustrated here are arranged in such a way that the extraction point 13b for the further transfer liquid from the top section 13 of the low-pressure column is above the feed point 14b for the further transfer liquid into the base section 14 of the argon column.

[0074] Integration of the components of the air separation plant 100 into cold boxes is illustrated in FIG. 2 in the form of a simplified side view, wherein the components of the air separation plant 100 are indicated with identical reference signs as explained above with respect to FIG. 1. As shown in FIG. 1, these are shown in side view, but even more greatly simplified. The fluid connections are not shown, but are evident corresponding to the representation according to FIG. 1. Two cold boxes 110 and 120 are illustrated, which, as explained below, contain components of the air separation plant 100 and thermally insulate them.

[0075] The base section 12 and the top section 13 of the low-pressure column are arranged in this case next to one another in such a way that an orthogonal projection of the base section 12 of the low-pressure column onto a horizontal plane H does not overlap with an orthogonal projection of the top section 13 of the low-pressure column onto the horizontal plane H, and the base section 14 and the top section 15 of the argon column are likewise arranged side by side in such a way that an orthogonal projection of the base section 14 of the argon column onto the horizontal plane H does not overlap with an orthogonal projection of the top section 15 of the argon column onto the horizontal plane H.

[0076] In contrast, the high-pressure column 11 is arranged below the base section 12 of the low-pressure column such that an orthogonal projection of the high-pressure column 11 onto the horizontal plane H overlaps with the orthogonal projection of the base section 12 of the low-pressure column onto the horizontal plane H.

[0077] The pure oxygen column 18 and the base section 14 of the argon column are arranged side by side such that an orthogonal projection of at least one upper part (further explanations above) of the pure oxygen column 18 onto the horizontal plane H does not overlap with the orthogonal projection of the base section 14 of the argon column onto the horizontal plane H,

[0078] Furthermore, in the air separation plant 100, the top section 13 of the low-pressure column and the top section 15 of the argon column are arranged side by side in such a way that the orthogonal projection of the top section 13 of the low-pressure column onto the horizontal plane H overlaps with the orthogonal projection of the top section 15 of the argon column onto the horizontal plane H.

[0079] The high-pressure column 11, the base section 12 of the low-pressure column and the base section 14 of the argon column and the pure oxygen column 18 are arranged in the first cold box 110, and the top section 13 of the low-pressure column and the top section 15 of the argon column are arranged in the second cold box 120, just like the pure argon column 20. This results in the advantages of a corresponding embodiment according to the invention.

[0080] As illustrated in dashed lines here, the subcooling heat exchanger 17 can in particular be arranged below the top section 13 of the low-pressure column in the second cold box 120 such that an orthogonal projection of the subcooling heat exchanger 17 onto the horizontal plane H overlaps with the orthogonal projection of the top section 13 of the low-pressure column onto this horizontal plane H in particular.

[0081] As explained, the top section 13 of the low-pressure column can be designed with a lower packing density than the top section 15 of the argon column, and the bottom section 14 of the argon column can be configured to separate methane. As explained above and in detail in FIG. 1, here as well, a lower region of the top section 13 of the low-pressure column and a lower region of the base section 14 of the argon column can also be fluidically coupled to an upper region of the base section 12 of the low-pressure column via a (common) pump.

[0082] FIG. 3 illustrates the components shown in FIG. 2 in plan view, wherein the horizontal plane H lies parallel to the paper plane, and reference is expressly made to the explanations relating to FIG. 2 for further details.